The new field of erodynamics consists of applications of the mathematical theories of nonlinear dynamics, chaos, and bifurcations to models in the social sciences, including economics. Here we give a capsule history of the field. Complex dynamical systems theory provides a new modeling strategy for social systems, which are usually too complicated to model without a theory which allows chaos and bifurcation. These new models contribute to the hermeneutical circle for evolving social structures, in which mathematical help in understanding may be very welcome. Even the simplest social systems, such as two persons or two nations, tax our intuitive cognitive strategies. Dynamical models may be used as navigational aids for cooperation, or conflict resolution, in many situations in which good will prevails, yet does not suffice. We now focus these cognitive strategies on individual psychology.

An early dynamical model for social systems, the first we know of, is the Verhulst model for population growth, of 1837. Later, in the context of the Great War, came Lanchester's model for war, in 1914, and Richardson's model for the arms race, in 1919. Next came dynamical models for economic systems, with Keynes, Schumpeter, and Von Neumann in the 1930s. Rashevsky, the founder of mathematical biology and editor of Richardson's papers, invented mathematical sociology during the Second World War. This sequence accelerated after World War II with the syntheses of general systems theory and cybernetics. In the mathematical branch of these movements, systems dynamics, we have the extensive development of models for factories, cities, nations, the world monetary system, and many other complex systems. The work of Jay Forrester was central to this growth. The independent development of dynamical systems theory after Poincare remained aloof from social applications until recently, and now a reunion of these two branches of mathematics is underway. In the Poincare lineage came the development of applied singularity theory by Rene Thom, its extensive application to social systems (as catastrophe theory) by Christopher Zeeman, and new dynamical models for economic systems by Radnor, Smale, and Chichilnisky in the 1970s. Since then, chaos theory has discovered systems with complex structure, and systems dynamics has discovered chaos.